This paper describes an exploration of how children adapt their interactions with different graphical user interfaces (GUIs) in varied task situations. The effect of computer exposure, computer knowledge, attitude and motivation (computer-friendliness) on childrens’ (age 13-15 years) adaptations and performance was studied. No significant effect of computer-friendliness was found influencing their adaptations and task-performance. The participants were exposed to two different known graphical user interfaces (GUIs). The empirical data shows that participants performed equally well on both the GUIs by adapting their interactions. Also it was observed that a GUI which is rich in features facilitates user adaptations in coping with differences in task complexities. Thus between-task adaptations and adaptivity can emerge as a new usability measure for comparing alternate GUI designs, for users of all age group.